Capítulos de libros de INSTITUTO DE BIOCIENCIAS DE LA PATAGONIA http://hdl.handle.net/11336/90270 2024-07-02T09:49:43Z 2024-07-02T09:49:43Z Bucci, Sandra Janet Goldstein, Guillermo Hernan Scholz, Fabian Gustavo Meinzer, Frederick C. http://hdl.handle.net/11336/200265 2023-06-12T13:47:17Z 2016-01-01T00:00:00Z

Physiological Significance of Hydraulic Segmentation, Nocturnal Transpiration and Capacitance in Tropical Trees: Paradigms Revisited Bucci, Sandra Janet; Goldstein, Guillermo Hernan; Scholz, Fabian Gustavo; Meinzer, Frederick C. Results from water relations and hydraulic architecture studies of trees from tropical savannas and humid tropical and subtropical forests were reanalyzed in view of paradigms related to the (i) physiological significance of hydraulic segmentation across trees with different life history traits and habitats, (ii) determinants of massive tree mortality, (iii) nocturnal transpiration, and (iv) the role of internal stem water storage. Stems and leaves of tropical and subtropical deciduous tree species are equally vulnerable to cavitation, whereas leaves of evergreen species are substantially more vulnerable than stems. Tree species from tropical ecosystems that do not experience seasonal droughts have stems and leaves with similar vulnerability to cavitation while trees from tropical ecosystems that experience seasonal droughts have leaves that are more vulnerable to drought induced cavitation compared to stems. Strong segmentation (whether hydraulic or vulnerability) during severe droughts may have an indirect negative impact on tree carbon balance. For example for Sclerolobium paniculatum, a widespread tree species in neotropical savannas and seasonally dry forests, the decrease in total leaf surface area per plant (which impact hydraulic architecture) during droughts help to maintain an adequate water balance but has large physiological costs: trees receive a lower return in carbon gain from their investment in stem and leaf biomass. Leaf hydraulic failure and carbon starvation may contribute to the massive, size-dependent mortality observed in this species. The functional significance of the widespread phenomenon of nocturnal transpiration in tropical trees is discussed. One of the most likely functions of nocturnal sap flow in savanna trees growing in nutrient poor soils appears to be enhanced nutrient acquisition from oligotrophic soils. Large capacitance plays a central role in the rapid growth patterns of tropical deciduous tree species facilitating rapid canopy access as these species are less shade tolerant than evergreen species. Higher growth rates in species with high capacitance could be achieved by keeping the stomata open for longer periods of time.

2016-01-01T00:00:00Z Scholz, Fabian Gustavo Bucci, Sandra Janet Meinzer, F. C. Goldstein, Guillermo Hernan http://hdl.handle.net/11336/199582 2023-06-05T16:18:25Z 2016-01-01T00:00:00Z

Maintenance of Root Function in Tropical Woody Species During Droughts: Hydraulic Redistribution, Refilling of Embolized Vessels, and Facilitation Between Plants Scholz, Fabian Gustavo; Bucci, Sandra Janet; Meinzer, F. C.; Goldstein, Guillermo Hernan Most woody dominated tropical ecosystems are subjected to droughtperiods of different lengths, from few days or weeks in wet forests to severalmonths in drought deciduous forests and savanna ecosystems. The roots duringthese low soil water availability periods may experience hydraulic and metabolicdysfunctions resulting not only in a substantial decrease in root growth rates, butalso in reduced water and nutrient uptake activity. We discuss three groups ofprocesses: (1) hydraulic redistribution, (2) refilling of embolized vessels, and(3) ecological facilitation, which can contribute together or in isolation to continuousroot activities despite low soil water availability. Furthermore they can helpavoid physiological uncoupling between above and belowground plant parts andthus help to preserve the integration of the root, stem and leaf hydraulic continuumwithin trees. The two mechanisms for refilling embolized vessels that help repairthe functionality of the water transport system discussed are the transient pressureimbalance between the xylem and surrounding tissues, and positive root pressures.Tree root systems not only obtain water from the soil to compensate for the waterlost through transpiration, but they can also move water from moist to dry layerswithin the soil profile along gradients in soil water potential. This process known ashydraulic lift or hydraulic redistribution provides water for reabsorption by roots ofthe same plant or by neighboring individuals with active roots in the soil wherewater is released through the process of ecological facilitation.

2016-01-01T00:00:00Z Alvarez, Hector Manuel Herrero, Ornella Marisa Lanfranconi, Mariana Patricia Silva, Roxana Alejandra Villalba, María Soledad http://hdl.handle.net/11336/157260 2022-05-11T18:36:41Z 2016-01-01T00:00:00Z

Biotechnological production and significance of triacylglycerols and wax esters Alvarez, Hector Manuel; Herrero, Ornella Marisa; Lanfranconi, Mariana Patricia; Silva, Roxana Alejandra; Villalba, María Soledad Global fat, oil, and wax ester demand is forecasted to increase in the next years. Steadily growing biodiesel requirements will lead to an increased demand for vegetable oils, in combination with a constant rise in the consumption of vegetable oil as food and feed. This situation will prompt the use of alternative sources for the production of oils and wax esters during the next years. In this context, microorganisms (yeasts, fungi, microalgae, and bacteria) are receiving increasing attention as alternative oils and wax esters sources. The knowledge acquired during the last decade about the production of bacterial triacylglycerols (TAG) and wax esters (WE) and their fundamental aspects could provide a new production platform for oils. The applied potential of bacterial TAG and WE may be similar to that of vegetable sources, such as additives for feed, cosmetics, oleochemicals, lubricants, and other manufactured products. In addition, bacterial oils could be used for biofuel production. The development of an industrial and commercially significant process may depend on the optimization of engineered cells and the technological procedures. This chapter will focus on the potential biotechnological application of TAG and WE produced by bacteria.

2016-01-01T00:00:00Z Hernández, Martín Alejandro Alvarez, Hector Manuel Lanfranconi, Mariana Patricia Silva, Roxana Alejandra Herrero, Marisa O. Villalba, María Soledad http://hdl.handle.net/11336/119583 2020-12-02T14:24:21Z 2019-01-01T00:00:00Z

Central metabolism of species of the genus Rhodococcus Hernández, Martín Alejandro; Alvarez, Hector Manuel; Lanfranconi, Mariana Patricia; Silva, Roxana Alejandra; Herrero, Marisa O.; Villalba, María Soledad Metabolism of Rhodococcus has evolved for adapting to a wide range of nutritional conditions. This adaptation often involves the flexibility of the central metabolism, which usually provides energy and precursors for biosynthesis processes, either during growth or during non-replicative metabolically active periods. The pathways of central metabolism are almost identical across widely divergent organisms, which share essentially the same metabolic network. However, this network possesses species-specific components, which depends on the biology of rhodococci. The central metabolism of members of Rhodococcus genus in the context of their physiology is the main topic of this chapter. An overview of main pathways of the central metabolism and their link with other metabolic processes is given. Glycolytic pathways, gluconeogenesis, phosphoenolpyruvate-pyruvate-oxalacetate node, tricarboxylic acid cycle (TCA), glyoxylate pathway and some litoautotrophic pathways are included.

2019-01-01T00:00:00Z